 
(* ::Section:: *)
(* SUNDelta *)
(* ::Text:: *)
(*SUNDelta[a, b]  is the Kronecker-delta for SU(N) with color indices a and b in the adjoint representation..*)


(* ::Subsection:: *)
(* See also *)
(* ::Text:: *)
(*ExplicitSUNIndex, SD, SUNF, SUNIndex, SUNSimplify, Trick.*)



(* ::Subsection:: *)
(* Examples *)



SUNDelta[SUNIndex[a],SUNIndex[b]]

SUNDelta[SUNIndex[a],SUNIndex[b]]SUNDelta[SUNIndex[b],SUNIndex[c]]

SUNSimplify[%]

SUNDelta[SUNIndex[a],SUNIndex[b]]

SUNDelta[SUNIndex[a],SUNIndex[b]]//StandardForm

SUNDelta[SUNIndex[a],SUNIndex[b]]//FCI//FCE//StandardForm

SD[a,b]//FCI//StandardForm


(* ::Text:: *)
(*The arguments of SUNDelta may also represent explicit integer indices via the head ExplictiSUNIndex. The difference is that SUNSimplify will only sum over symbolic indices.*)


SUNDelta[SUNIndex[a],ExplicitSUNIndex[2]]SUNDelta[SUNIndex[a],SUNIndex[b]]SUNDelta[SUNIndex[c],ExplicitSUNIndex[2]]//SUNSimplify

%//StandardForm

SD[1,2]//FCI//StandardForm
